Extreme low and high temperature treatments as a non-chemical control strategy for the almond moth, Ephestia cautella in dried figs

Abstract

Mortality responses of different developmental stages of the almond moth, Ephestia cautella (Walker) (Lepidoptera: Pyralidae), to extreme low and high temperatures were evaluated under laboratory and field-scale conditions to assess the feasibility of temperature-based control strategies for dried fruit pests. Eggs and pupae were tested in three age groups (0–24, 24–48, and 48–72 h), larvae as young (15 days after hatching) and mature (25-28 days after hatching) stages, and adults at 1–2 days post-emergence. Individuals were exposed to low temperatures (5, 0, −5, −10, −15, and −18 °C) and high temperatures (45, 50, and 55 °C) for different exposure durations. Mortality increased significantly with decreasing temperature under cold treatment with increasing temperature under heat treatment and with prolonged exposure in both treatments. Complete mortality was achieved in all life stages and age groups after 1 h of exposure at −18 °C and −15 °C. High-temperature treatments resulted in 100% mortality following 12 h at 45 °C, 3 h at 50 °C, and 1 h at 55 °C. Age-related tolerance was observed, with older developmental stages generally exhibiting greater resistance under moderate exposure conditions. Field-scale trials confirmed laboratory findings, demonstrating complete mortality at selected lethal temperature–time combinations. These results indicate that extreme temperature applications provide an effective, residue-free, alternative to chemical insecticides for managing E. cautella infestations in dried fruit systems. The integration into postharvest management programs may contribute to improved product safety while reducing insecticide dependence and resistance development.